An undocumented immigrant from Guatemala waits for his turn for a phone call after arriving to Announciation House, an organization that provides shelter to immigrants and refugees, in El Paso, U.S. Jan. 17, 2017. REUTERS/Tomas Bravo

President Donald Trump is taking steps Wednesday to fulfill a campaign promise of building a wall along the Mexico-U.S. border, according to reports. Press secretary Sean Spicer said the president would sign two executive orders designed to begin building the wall and enforce stricter immigration measures.

"Low-skilled immigration... continues to reduce jobs and wages for American workers," Trump said in a campaign speech in September.

Is this true? Do undocumented workers take American jobs? There’s no straightforward answer to this question.

There were about 11 million unauthorized immigrants in the U.S. in 2014 -- 3.5 percent of the nation’s population -- and that number has remained about the same since 2009, according to the Pew Research Center. In fact, that figure is down from 2007, when the number of unauthorized immigrants in the U.S. peaked at 12.2 million. So, despite political rhetoric, illegal immigration hasn’t been on the rise.

In 2014, about 8 million unauthorized immigrants were employed, which accounted for 5 percent of the American workforce.

When it comes to U.S.-born citizens, the unemployment rate has dropped (it's now at 4.7 percent, according to Bureau of Labor Statistics data). But the percentage of people who are actually in the workforce has fallen over the past few years, as well.

The majority of unauthorized immigrants don’t work in the same industries as native-born workers. Another report from Pew found that undocumented immigrants tended to work in agriculture, leisure and hospitality, and construction. U.S.-born workers, on the other hand, were much more likely to work in education and health services, financial activities, and public administration.

Plus, the previous point holds true even if when comparing only workers who don’t have a high school diploma, which some economists argue is a better comparison because most unauthorized immigrants work in low-skilled jobs.

The top three jobs for immigrants without high school diplomas were maids and housekeepers, cooks, and agriculture workers, according to the Urban Institute. The top three occupations for native-born workers without a high school diploma? Cashiers, truck drivers and janitors. Which means that Americans who didn’t finish high school tend to look for different jobs than immigrants with similar education levels.

A report published last year found that there are “little to no negative effects on overall wages and employment of native-born workers in the longer term,” according to Francine D. Blau, economics professor at Cornell University, who led the study.

In fact, the people who were more likely to be replaced by new immigrants were older immigrants who had moved to the U.S. years ago. Teenagers were also likely to lose hours of work -- but not less likely to find a job -- thanks to competition with immigrant workers, the study found.